Dr. Emin Tuncay Ustuner, a plastic surgeon in Ankara, Turkey, came up with the theory that calls out gravity’s “force of downward pull ... on the scalp” as the main culprit in male pattern baldness. But there’s a little more to it, and it involves a potent form of the male sex hormone testosterone, known as dihydrotestosterone (DHT), which has been known to thin hair follicles in the scalp.

Dr. Ustuner’s theory posits that aging, and to a lesser extent testosterone, causes people to lose the fatty tissue that lies under their scalp. This tissue is able to keep itself “well hydrated” during youth, thereby protecting the hair follicles from gravitational pressure. But as it’s lost, pressure increases on the follicles, and the body tries to compensate for the added pressure by sending more testosterone to help grow hair. This leads to an overabundance of DHT, and what was once just a contributing factor to lost fatty tissue becomes a major factor, according to a press release.

These processes become a “vicious cycle” in which DHT tries to grow hair, but causes the fatty tissue to dissolve, subsequently leading to more gravitational pressure, Dr. Ustuner said. For this reason, many people lose hair on the top of their heads first, and then at the front of the head, where weight from facial tissue pulls down further, he said. Hair remains on the side of the head because the ears are there to provide support.

“There is not another theory that reasonably and satisfactorily explains hair loss in AGA without ascribing a function to DHT that is opposite to its known function,” he wrote, according to the statement. While certain theories say that genetically predisposed people are susceptible to these hormonal patterns, Dr. Ustuner said that increases of DHT in the scalp are “not an occurrence directly determined by genes.”